Workaround:
//Taken from the above demonstration
Maptext3
screen_loc = "SOUTHWEST"
maptext_height = 64
maptext_width = 64
maptext = "<span style='color:#00b8ff;font-weight:bold;font-size:11px;text-align:left;' valign='top'>Maptext3</span>"
What is wrong: When vertical-align is used in an in-line style, it breaks the style.
How to workaround it: Use valign instead outside of style.